Hallo,
Michael tell me pleas what is the right way to make this:



This is the SIMPLE example of what I wanted to know - how to make holes or just draw on curved objects. Some times I think it would be great to have something like - draw on surface . Because using project is not very convenient way, flow is also not good in every situation. Pleas tell me how to work on curved surfaces, in polygonal it is very easy.

More complicated to make sense:

Hi Andrei, the main way is to do a 2D drawing and then use boolean difference to use that 2D curve as the cutting object which does then do a projection of the planar object onto the surface.

You can place points snapped directly on to surfaces, but for curved surfaces just placing a few points of a curve does not make the full curve itself to on the surface unless the surface is planar. So usually direct drawing of curves on surfaces is only done for planar surfaces and not on curved surfaces.

There is a different kind of projection called "Closest point" projection which would probably help you with some of these cases - currently closest point projection in MoI does not work very well though so until that is fixed up you usually will need to use planar projection and just arrange the planar curves as needed to make the cuts you want.

When closest point projection is working better then you'll be able to use a somewhat different method of drawing curves with control points directly snapped on to surfaces, and then using that 3D bent curve as a cutting curve in trim to cut a surface (even though it's not all the way on the surface), then you'd thicken the cut surface using Shell. Right now that method does not work all that well though because of the closest point (in Rhino called "pullback") projection is problematic.

- Michael

>Hi Andrei, the main way is to do a 2D drawing and then use boolean difference to use that 2D curve as the cutting object which does then do a projection of the planar object onto the surface.

Yep Michael I know about this but if surface is very curved I have to orient all profiles along it to get more good result, but it is still not very precise method.

Hi Andrei,

> Yep Michael I know about this but if surface is very curved I have to orient all profiles along it to get more
> good result, but it is still not very precise method.

Still, it's the main method currently, either that or Flow if you have a more detailed pattern that you want to map on to a curved surface.

You can also use the Transform > Orient command to help with positioning a planar profile onto a surface so that a center point of it aligns to the surface normal.

See here for some examples of the Orient command:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3977.2


If the surface is very curved then mostly you'll probably want to use Flow instead.


- Michael

We also had some discussion about this very topic here where you can configure your ini file to draw in ortho view.

Bit of a pain I know, but does work well.

http://moi3d.com/forum/messages.php?webtag=MOI&msg=6171.1

Those shapes you've drawn do seem like an ideal candidate for flow but if you've already tried it, then how about making your curved shape, giving it thickness and then drawing a temporary construction planes where you want the holes and then Boolean the holes.

Thanx) Kevjon, what does it mean draw in ortho view?

Draw a curve on a surface in ortho view.

Moi normally only allows you to draw a curve on a surface in perspective view.